How to Alter the Depth of Field on the Canon Rebel T5/1200D
The aperture setting, or f-stop on the Canon Rebel T5/1200D, affects depth of field, or the distance over which sharp focus is maintained. With a shallow depth of field, your subject appears more sharply focused than faraway objects; with a large depth of field, the sharp-focus zone spreads over a greater distance.
When you reduce the aperture size — “stop down the aperture,” in photo lingo — by choosing a higher f-stop number, you increase depth of field. As an example, see the figure below. Notice that for both shots, the photographer established focus on the fountain statue.
Notice that the background in the first image, taken at f/13, is sharper than in the right example, taken at f/5.6. Aperture is just one contributor to depth of field, however; the focal length of the lens and the distance between that lens and your subject also affect how much of the scene stays in focus.
One way to remember the relationship between f-stop and depth of field, or the distance over which focus remains sharp, is simply to think of the f as focus: The higher the f-stop number, the larger the zone of sharp focus.